1. Technical Field
The present disclosure relates to a wireless communication device, and, more particularly, to a wireless communication device that enhances transmitting and receiving performance in a near-field communication (NFC) apparatus, and a mobile apparatus including the wireless communication device.
2. Discussion of the Related Art
Recently, a mobile apparatus, such as a smart phone having a near-field communication (NFC) function, is being widely used.
NFC technology has been developed by a NFC forum. According to NFC technology, data are transferred using a contactless interface between NFC apparatuses. NFC has an active mode (that is, a reader mode) and a passive mode (that is, a card mode).
In the active mode, an NFC apparatus operates like a radio frequency identification (RFID) reader that writes data in a RFID tag and reads data from the RFID tag. For example, in the active mode, the NFC apparatus emits a magnetic field, transmits data by modulating the amplitude of the magnetic field, and receives data by an inverse modulation.
In the passive mode, the NFC apparatus operates like an RFID tag. For example, in the passive mode, the NFC apparatus does not emit a magnetic field, but receives data by modulating the amplitude of a magnetic field emitted by an external reader and transmits data by an inverse modulation.
When transmitting data, the NFC apparatus typically generates a carrier signal using a digital amplifier. Therefore, harmonics may be generated together with the carrier signal. If the harmonics are not filtered out, transmitting performance may be degraded.
In addition, since the NFC apparatus receives data using a magnetic field generated by the NFC apparatus in the active mode and receives data using a magnetic field generated by an external reader in the passive mode, intensities of received signals in the active mode and the passive mode are different from each other.
Therefore, a need exists for an NFC apparatus that eliminates unwanted transmit harmonics while correctly receiving data provided by signals of different intensities.